Re: Grouping (yet again)

If you're ok using Saxon 7.0 (which implements the new grouping
functionality of XSLT 2.0), then here's the XSLT 2.0 (draft)
solution:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">
  <xsl:output indent="yes"/>
  <xsl:template match="/">
    <graph>
      <!-- Group first by @group -->
      <xsl:for-each-group select="list/datum" group-by="@group">
        <data group="{@group}">
          <!-- Within group, then group by YYYYWW number (defaults to ascending) -->
          <xsl:for-each-group select="current-group()" group-by="concat(@year,@week)">
            <xsl:sort data-type="number" select="number(concat(@year,@week))"/>
            <datum week="{concat(@year,@week)}">
              <!-- Within week, group by dir, ordering descending by sum of @value -->
              <xsl:for-each-group select="current-group()" group-by="@dir">
                <xsl:sort data-type="number" order="descending"
                          select="sum(current-group()/@value)"/>
                <datum value="{sum(current-group()/@value)}" dir="{@dir}"/>
              </xsl:for-each-group>
            </datum>
          </xsl:for-each-group>
        </data>
      </xsl:for-each-group>
    </graph>
  </xsl:template>
</xsl:stylesheet>

On your data, this produces for me:

<?xml version="1.0" encoding="utf-8"?>
<graph>
   <data group="Downloads">
      <datum week="200143">
         <datum value="350" dir="xerces-j"/>
         <datum value="115" dir="soap"/>
         <datum value="87" dir="batik"/>
         <datum value="81" dir="xerces-c"/>
         <datum value="74" dir="axis"/>
         <datum value="72" dir="fop"/>
         <datum value="39" dir="cocoon2"/>
         <datum value="38" dir="xalan-j"/>
         <datum value="36" dir="cocoon"/>
         <datum value="29" dir="crimson"/>
         <datum value="8" dir="xerces-p"/>
         <datum value="3" dir="xalan-c"/>
      </datum>
      <datum week="200144">
         <datum value="115" dir="soap"/>
         <datum value="87" dir="batik"/>
         <datum value="74" dir="axis"/>
         <datum value="72" dir="fop"/>
         <datum value="46" dir="cocoon2"/>
         <datum value="36" dir="cocoon"/>
         <datum value="29" dir="crimson"/>
         <datum value="3" dir="xalan-c"/>
      </datum>
   </data>
   <data group="Uploads">
      <datum week="200143">
         <datum value="91" dir="batik"/>
         <datum value="74" dir="axis"/>
         <datum value="29" dir="crimson"/>
         <datum value="7" dir="cocoon2"/>
         <datum value="3" dir="cocoon"/>
      </datum>
      <datum week="200144">
         <datum value="700" dir="xerces-j"/>
         <datum value="230" dir="soap"/>
         <datum value="162" dir="xerces-c"/>
         <datum value="144" dir="fop"/>
         <datum value="76" dir="xalan-j"/>
         <datum value="29" dir="crimson"/>
         <datum value="16" dir="xerces-p"/>
         <datum value="6" dir="xalan-c"/>
      </datum>
   </data>
</graph>

_____________________________________________________________________
Steve Muench - Developer, Product Manager, XML Evangelist, Author
"Simplifying J2EE and EJB Development with BC4J"
http://otn.oracle.com/products/jdev/htdocs/j2ee_with_bc4j/j2ee_with_bc4j.html
"Building Oracle XML Applications" - www.oreilly.com/catalog/orxmlapp



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